The Tracker

"You've come to a wild place," he tells me when I arrive at his field station in southeastern Sumatra's Way Kambas National Park. Rhinos, cobras, vipers, elephants - there's plenty here that's lethal.

"And for god's sake," he adds without smiling, "stay off the road after 5:30 p.m., when the tigers begin to prowl."

Moments later, as if according to a script, Tilson's assistant shouts,

"Elephant in camp! Elephant! Everyone inside! Turn off the lights!"

And for the next hour a bull elephant strolls around, poking its trunk at cars and buildings before vanishing into the forest.

Just another day in Tilson's life in Sumatra, one of two poles of this wildlife conservationist's work. The other is half a world away in Minnesota, where he is director of conservation at the Minnesota Zoo, and where he also heads up the Tiger Species Survival Plan, which links North American zoos in an effort to protect the genetic diversity of captive tigers. Here in Way Kambas, he manages the Sumatran Tiger Project, designed to preserve the endangered animal in its native habitat.

Wilderness and wild animals are practically in Tilson's genes. He grew up in Montana, near Yellowstone National Park, he says, "hunting and fishing with my father every weekend I can recall Ð enchanted with Yellowstone and wildlife conservation."

He earned a bachelor's degree in entomology at the University of California, Davis, and considered becoming a veterinarian. "But what I really wanted," he recalls, "was to be out in the wilderness."

And now he's quite happy to be there. "Doing this work you get to go to some of the most fiercely wonderful areas in the world," he says. "I wish I could have more impact on protecting tigers, but side from that, I wouldn't trade my life for anything."

Tilson first came to Southeast Asia in 1969, working as a Peace Corps volunteer in Malaysia. Later, as a graduate student at Davis, he studied gibbons along Sumatra's western coast. (A tattoo of a gibbon on his left forearm recalls those days). Eventually he became director of research at the Minnesota Zoo Ð which had an exceptional collection of Siberian tigers Ð where he was a protege of Ulysses S. Seal, an internationally known specialist in wildlife endocrinology and genetics.

But after nearly 15 years there, he was itching to do more field research, and since he was already spending more and more time in Indonesia Ð his work with rhinoceroses on Java had brought Tilson back to the region Ð and was familiar with tigers, the Indonesian jungle, and the local language and culture, studying Sumatra's tiger population seemed logical.

"I wanted to go beyond the zoo fence and work in the habitat where tigers live," he says.

In Way Kambas he found the ideal setting for his research: 320,000 acres of lush forest with abundant tiger food, such as deer and wild pigs. But estimates of the tiger population Ð it was thought that perhaps 20 of Sumatra's estimated 500 wild tigers lived there Ð were little more than guesses, and Tilson realized that before the cats could be saved, they had to be counted. But how to locate such furtive animals in thick tropical forests? He decided to use a new technology Ð flash-equipped cameras rigged to infrared motion-detectors: When a large animal passed by, the shutter would be released.

Late in 1995 Tilson and his team set a "trap line" of such cameras at points where the pattern of water and wetlands funneled animals onto a single trail. Soon a parade of tigers appeared on film, each distinguished by a pattern of stripes as unique as a fingerprint. Over time Tilson's team identified 40 tigers in Way Kambas Ð double the original estimate Ð including three sets of newborn cubs.

As the work of counting tigers proceeds apace, he can turn increasingly to the work of protecting them. One big problem is poaching, which has three separate aspects. The first is the illegal hunting of tigers to supply the black market in Asia, where tiger parts are believed to have nearly magical restorative and curative capacities. Second is poaching by locals, who use tiger parts similarly, seeking to gain some of the power of the near-mythical animals. And a third is the poisoning of tigers by villagers after an attack on a domestic animal or even a human.

"All three translate to tiger losses," says Tilson, "but no one knows how many deaths are caused by each kind."

To combat the problem, Tilson has raised funds to hire patrols that comb Way Kambas for poachers. (They also monitor Tilson's camera traps.) Since the teams were deployed six months ago, poaching in the park has declined dramtically.

"The patrols are actually doing what they are supposed to do," he reports, "creating a deterrence for anyone who wants to come in."

Considering the danger tigers pose, I am surprised one afternoon to see Tilson jog into camp on a narrow forest road, his T-shirt soaked and his face dripping with sweat.

Wasn't he afraid of tigers?

"Never had a problem," he says, though he did once "nearly jog into an elephant," which was about ten feet away when it trumpeted and thrashed a bush with its trunk. But Tilson has never seen a Sumatran tiger in the wild.

"I go out in the field," he says. "I sleep out in the wild. I have walked a full day - anywhere from 12 to 16 kilometers on trails frequented by tigers - and I have not seen any sign other than maybe a scratch mark that could be 30 days old. And yet I know I'm walking through an area where several dozen tigers are alive and walking around."